A groundbreaking study has revealed that global ocean analysis products can serve as a viable alternative to costly in-situ sound speed measurements for precise seafloor positioning. Published in Satellite Navigation on June 30, 2025, the research highlights the potential of the HYbrid Coordinate Ocean Model (HYCOM) global ocean analysis to achieve centimeter-level accuracy in seafloor positioning, mirroring the precision of traditional methods but at a fraction of the cost.
Accurate seafloor positioning is indispensable for a variety of scientific and industrial applications, including the study of tectonic movements, earthquakes, and marine resource exploration. The Global Navigation Satellite System-Acoustic (GNSS-A) technique, which combines satellite and acoustic measurements, has been the gold standard for achieving such accuracy. However, the reliance on in-situ sound speed profiles (SSPs) has posed significant financial and logistical hurdles, prompting the search for more cost-effective solutions.
The study, conducted by researchers from the First Institute of Oceanography, Ministry of Natural Resources and Shandong University of Science and Technology, evaluated the effectiveness of HYCOM global ocean analysis products in GNSS-A positioning. The findings were promising, with global ocean analysis derived SSPs delivering horizontal positioning accuracy of 0.2 cm (RMS) and vertical accuracy of 2.9 cm (RMS), closely matching the accuracy of traditional in-situ measurements.
Dr. Yanxiong Liu, the corresponding author of the study, emphasized the practical implications of these findings, stating, "Our results confirm that global ocean analysis sound speed profiles are a practical alternative to in-situ measurements. This advancement not only cuts costs but also expands access to seafloor geodetic technology for broader scientific and industrial applications."
The implications of this study are far-reaching. By making GNSS-A positioning more affordable and accessible, it opens the door to more frequent and high-precision seafloor surveys, particularly in earthquake-prone regions. Offshore industries stand to benefit from reduced costs in seafloor positioning for infrastructure projects, while the scientific community gains enhanced tools for studying seafloor plate tectonics. Furthermore, this innovation holds promise for the navigation of unmanned vehicles and deep-sea exploration, marking a significant step forward in marine geodesy and our understanding of the seafloor.
